Editing GIS in the Philippines (section)

== I. Definition and Description: Geographic Information System ==

GIS is a rapidly growing technological field that incorporates graphical features with tabular data in order to assess real-world problems. What is now the GIS field began around 1960, with the discovery that map could be programmed using simple code and then stored in a computer allowing for future modification when necessary. This was a welcome change from the era of hand cartography when maps had to be painstakingly created by hand; even small changes could require the creation of a new map. The earliest version of a GIS was known as computer cartography and involved simple line work to represent land features. From that evolved the concept of overlaying different mapped features on top of each other to determine patterns and causes of spatial phenomenon.<br /><br />
The capabilities of GIS are a far cry from the simple beginnings of computer cartography. At the simplest level, GIS can be thought of as a high-tech equivalent of a map. However, not only can paper maps be produced far quicker and more efficiently, the storage of data in an easily accessible digital format enables complex analysis and modeling not previously possible. The reach of GIS expands into all disciplines and has been used for such widely ranged problems as prioritizing sensitive species habitat to determining optimal real estate locations for new businesses.<br /><br />
The key word to this technology is Geography - this usually means that the data (or at least some proportion of the data) is spatial, in other words, data that is in some way referenced to locations on the earth. Coupled with this data is usually tabular data known as attribute data.  <br />
A geographic information system (GIS) integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information in order to solve complex planning and management problems. A simple definition is that GIS is a computer system which can hold and use data in describing places on the earth’s surface.<br /><br />
A GIS can be divided into five components: People, Data, Hardware, Software, and Procedures.  People are the vital component of GIS. They are the ones who actually make the GIS work.  They are responsible for maintenance of the geographic database and provide technical support.  People also need to be educated to make decisions on what type of system to use.  People associated with a GIS can be categorized into: viewers, general users, and GIS specialists. Viewers are the public at large whose only need is to browse a geographic database for referential material. General Users are people who use GIS to conducting business, performing professional services, and making decisions.  GIS specialists are responsible for the maintenance of the geographic database and the provision of technical support to the other two classes of users. <br /><br />
Procedures include how the data will be retrieved, input into the system, stored, managed, transformed, analyzed, and finally presented in a final output.  <br />
Hardware consists of the technical equipment needed to run a GIS including a computer system with enough power to run the software, enough memory to store large amounts of data, and input and output devices such as scanners, digitizers, GPS data loggers, media disks, and printers. <br />
Software packages must be capable of data input, storage, management, transformation, analysis, and output, but the appearance, methods, resources, and ease of use of the various systems may be very different. Today’s software packages are capable of allowing both graphical and descriptive data to be stored in a single database, known as the object-relational model.  <br />


Perhaps the most time consuming and costly aspect of initiating a GIS is creating a database.  There are several things to consider before acquiring geographic data.  It is crucial to check the quality of the data before obtaining it.  Errors in the data set can add many unpleasant and costly hours to implementing a GIS and the results and conclusions of the GIS analysis most likely will be wrong.  <br />

Geographic information system technology can be used for scientific investigations, resource management, asset management, archaeology, environmental impact assessment, urban planning, cartography, criminology, geographic history, marketing, logistics, Prospectivity Mapping, and other purposes. For example, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business location to take advantage of a previously under-served market. <br />

Common practical applications include mapping out environmental layers to characterize a site and predict site potential. GIS helps in routing of roads, transmission lines, pipelines, sewer, and network analysis. It maps and manages urban infrastructure including base maps, tax, cubs, water supply, drainage, electricity, telephone, and gas. Another application is spatially examining socio and economic indicators of the population and their use in planning and growth management. There are literally thousands of applications of GIS because no project is ever started without first asking ‘where’. <br />